Nelson tells Billboard.com the three of them are working on an album together. But he doesn't indicate when they'll be presenting it to the public. Willie says it "could be" a 2014 release, but adds that they'll issue the disc once they "get it together."

On the Grammys Nelson, Kristofferson, and Haggard teamed up for a tribute to "outlaw" country. Blake Shelton also took part in the segment, which featured performances of "Highwayman," "Okie From Muskogee," and "Mammas Don't Let Your Babies Grow Up To Be Cowboys." The set marked the first time Haggard had ever performed on the Grammys.

And the upcoming album is thought to be the first collaborative studio project for Kristofferson and Haggard. They've both worked with Nelson before. Willie and Kris were in The Highwaymen together, while Willie and Hag teamed up on the 1983 album "Pancho & Lefty."